Combined System of intercooled Recuperative Gas Turbine and Organic Compound Bottoming Cycle

ABSTRACT

The invention discloses a combined system of intercooled recuperative gas turbine and organic compound bottoming cycle, comprising intercooled recuperative gas turbine, organic-gas heater, organic working substance turbine, condenser and pressure pump, the organic-gas heater is connected to recuperator of intercooled recuperative gas turbine, the organic-gas heater is connected to organic working substance turbine, the organic working substance turbine is connected to condenser, the condenser is connected to pressure pump, the pressure pump is connected to intercooler of intercooled recuperative gas turbine, the intercooler is connected to organic-gas heater; by adopting the invention, it can overcome problems of insufficient heat exchange and large exergy loss in intercooler caused by constant evaporation temperature when using subcritical organic Rankine cycle and Kalina cycle, and can also ensure that the entire system maintains a higher power generation efficiency than intercooled recuperative gas turbine and improves gas turbine power output in hot climates.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to gas turbine, in particular to a combined system of intercooled recuperative gas turbine and organic compound bottoming cycle.

2. Description of the Related Art

Since the invention of the gas turbine in the 1930s, as an important engine, it has been widely used in aviation, marine propulsion, and land-based power plants. Gas turbines adopting the air Brayton cycle have higher thermal efficiency and output power, and measures to continue to improve the cycle efficiency include increasing turbine inlet temperature, adding reheating, intercooling and regeneration devices, injecting steam into the turbine, adding the steam Rankine cycle as the bottoming cycle, and etc.

In terms of the power of marine gas turbines, in order to improve the efficiency of marine gas turbines, in 1946, the Rolls-Royce Holdings PLC signed a contract with the British Navy for the production of ship intercooled recuperative (ICR) gas turbine RM60, however, it was limited by heat transfer technology, causing problems such as oversized equipment and dust accumulation in the heat exchanger, thereby the contract was finally discontinued. With the continuous improvement of the working parameters of marine gas turbines, the improvement of the efficiency of the simple cycle has reached a bottleneck, in addition, the progress of heat exchanger technology in recent years has made the intercooled recuperative technology a hot spot again, and at the beginning of this century, WR-21 Type intercooled recuperative marine gas turbine, led by Britain and America and participated by Germany and France, has achieved great success, after being arranged in destroyers and other ships, it has achieved a fuel consumption reduction of about 30%, which has attracted great attention from the navies of various countries, and China has also begun to develop intercooled recuperative marine gas turbines. However, the intercooled recuperative gas turbine technology also has a common defect of gas turbines: the performance declines sharply in very hot climates, which will inevitably affect the performance of ships in tropical ocean areas. In addition, the intercooling recuperative technology is also a simple cycle in nature, and there is no bottoming cycle to cooperate with, although the efficiency thereof is higher than that of ordinary non-intercooling commercial gas turbines, it is not as good as the gas-steam combined cycle, therefore, gas-steam combined cycle power was tried many times on ships many times, however, it has not been successfully applied except on a few large cruise ship, even failed on 10,000-ton warship attempted by United States Navy. In all fairness, the steam Rankine cycle is a very efficient bottoming cycle, but the disadvantage thereof is that the system is complex, bulky and heavy, and lacks quick response, therefore it is not suitable for most ships.

As far as land-based gas turbine power plants are concerned, they are basically dominated by non-intercooled recuperative gas turbines, the gas-steam combined cycle has been widely used, the latest H-class gas turbines with three-pressure reheating steam cycle have reached 63-64% effectiveness. Because there is enough space on land and water is a common cheap substance in many areas, the steam Rankine cycle has been proved to be a successful bottoming cycle in practice. However, the gas-steam combined cycle is not perfect, firstly, the gas turbine is very sensitive to the external atmospheric environment, especially the temperature, even if it was equipped with water spray cooling measures, the output of the combined cycle in hot and humid summer will drop by about 10-20%. Secondly, it has become difficult or even impossible to construct a gas-steam combined cycle in arid or even desert areas due to limited water source. Meanwhile, as renewable energy booms, thermal power plants are required to quickly change the load to cooperate with unstable renewable energies—when the wind stops blowing it demands flexible gas turbine plants to quickly step in. However, the great inertia of steam turbine cycle limits standard gas-steam combined cycle for peaking load.

In conclusion, the combined gas-steam cycle is not available on most ships because it is bulky and heavy and lacks quick response, the efficiency of sole intercooled recuperative gas turbines is not so good as that of the gas-steam combined cycle, and adopting intercooled recuperative gas turbine technology on board cannot overcome the problems of drastically degraded performance in very hot climates and the poor performance of ships in tropical oceans; also it cannot overcome the problem that the gas-steam combined cycle cannot be used on dry or desert land, and cannot solve the problem of the gas turbine's serious performance degradation in hot weather.

Due to the technical problems of large equipment and large water consumption in the gas-steam combined cycle, it is not easy to use it in water-scarce places such as ships and arid deserts, therefore, a lot of research of the bottoming cycle of the Brayton cycle in the intercooled recuperative gas turbine in the industry, at present, some people in the art use the subcritical organic Rankine cycle as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, also some people use Kalina cycle ammonia water as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, to improve the efficiency of the intercooled recuperative gas turbine; however, the power generation efficiency is not high enough when using subcritical organic Rankine cycle and Kalina cycle (ammonia/water) as the bottoming cycle of the intercooled recuperative gas turbine, and with deep research of inventors, it was found that when the subcritical organic Rankine cycle and Kalina cycle ammonia water are used as bottoming cycle, there will be respectively constant evaporation temperature of subcritical organic working substance and ammonia/water, resulting in insufficient heat exchange and large exergy loss in the intercooler.

Moreover, whether using the subcritical organic Rankine cycle as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, using Kalina cycle ammonia water as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, or adopting gas-steam combined cycle power system, it cannot overcome the problems that the gas turbine is very sensitive to the external atmospheric environment, and the power output will be significantly reduced in the hot and humid summer.

SUMMARY OF THE INVENTION

In view of the disadvantages in the prior art, the invention provides a combined system of intercooled recuperative gas turbine and organic compound bottoming cycle, to solve the problems that when the subcritical organic Rankine cycle and Kalina cycle ammonia water are used as bottoming cycle, there will be respectively constant evaporation temperature of subcritical organic working substance and ammonia water, resulting in insufficient heat exchange and large exergy loss in the intercooler.

A combined system of intercooled recuperative gas turbine and organic compound bottoming cycle, comprising intercooled recuperative gas turbine, organic-gas heater, organic working substance turbine, condenser, pressure pump and organic working substance preheater, the organic-gas heater is connected to recuperator of the intercooled recuperative gas turbine, the organic-gas heater is connected to the organic working substance turbine, the organic working substance turbine is connected to the condenser, the condenser is connected to the pressure pump, the pressure pump is connected to intercooler of the intercooled recuperative gas turbine, the intercooler is connected to the organic-gas heater; the intercooler is connected in parallel to the organic working substance preheater; the condenser is used for cooling and condensing the organic working substance into liquid and delivering the same to the pressure pump, the pressure pump is used for pressurizing the organic working substance to exceed the critical pressure and delivering the same to the intercooler, the intercooler is used for preheating the organic working substance and delivering the same to the organic-gas heater, the organic-gas heater is used for heating the organic working substance to above the critical temperature and delivering the same to the organic working substance turbine, the organic working substance turbine is making use of the expansion of the organic working substance and delivering the same to the condenser; the organic-gas heater cools the gas input from the recuperator and discharges the same thereafter. The intercooled recuperative gas turbine Brayton cycle is the topping cycle, and the organic-gas heater, organic working substance turbine, the condenser and the pressure pump form a supercritical organic Rankine cycle, the supercritical organic Rankine cycle is used as the bottoming cycle of the combined system, in actual use, the condenser cools and condenses the organic working substance into liquid and delivers the same to the pressure pump, the pressure pump pressurizes the organic working substance to supercritical pressure and delivers the same to the intercooler, after entering into the intercooler, the organic working substance absorbs heat of the compressed air in the intercooler, and enters into the organic-gas heater, the organic-gas heater conducts heat exchange between the gas from the recuperator and the entered organic working substance, to heat up the organic working substance above supercritical temperature, and the organic working substance enters into the organic working substance turbine to generate power, the organic working substance turbine delivers the organic working substance into the condenser, thereby the supercritical/trans-critical organic Rankine cycle is realized, The advantages thereof are that the supercritical organic working substance eliminates other cooling substance and obtains energy directly from compressed air in the intercooler, and absorbs heat of gas discharged from recuperator in the organic-gas heater, the temperature of gas heat is in a range of 60-350° C. while the organic Rankine cycle has an advantage over the steam Rankine cycle, the heated organic working substance enters the organic working substance turbine for power generation, the supercritical organic Rankine cycle completely absorbs the waste heat of the topping cycle and the supercritical organic working substance is heated to above the supercritical temperature through the intercooler and the organic-gas heater, thereby improving bottoming cycle efficiency; in addition, because the organic working substance is pressurized to supercritical pressure by the pressure pump to form a supercritical fluid, and the supercritical fluid does not have a constant evaporation temperature, thereby overcoming the disadvantages of constant evaporation temperature of subcritical organic working substance and ammonia water, resulting in insufficient heat exchange and large exergy loss in the intercooler.

Preferably, the invention also comprises first throttle valve, second throttle valve, first compressor and second compressor, the throttle valves are connected to the condenser, the throttle valves are connected to inlet air cooler of the intercooled recuperative gas turbine through the second throttle valve, the inlet air cooler is connected to the first compressor through the second compressor, the first compressor is connected to the condenser; organic working substance discharged by the condenser enters into the first throttle valve and the second throttle valve, and the first throttle valve and the second throttle valve cools the entered organic working substance and discharges the same into the inlet air cooler, the organic working substance in the inlet air cooler absorbs heat and enters into the first compressor and the second compressor, and enters into the condenser after pressurized by the first compressor and the second compressor. Moreover, whether using the subcritical organic Rankine cycle as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, using Kalina cycle ammonia water as the bottoming cycle of the intercooled recuperative gas turbine and form a combined system with intercooled recuperative gas turbine, or adopting gas-steam combined cycle power system, it cannot overcome the problems that the gas turbine is very sensitive to the external atmosphere, and the power output will be significantly reduced in the hot and humid summer. The invention is provided with throttle valves and compressors, the throttle valves are connected to the condenser, and the organic working substance output from the condenser is divided into two paths, one way enters the pressure pump to pressurize for supercritical organic Rankine cycle, the other way enters the throttle valve and produces significant temperature drop, and enters the inlet air cooler to absorb heat, after heating up, enters the compressor and enters into the condenser after pressurized, thereby forming vapor compression refrigeration cycle, low-temperature organic working substance enters the inlet air cooler to cool the inlet air, thereby improving the power output in hot climates, which has great significance for land-based gas turbine power plants and marine gas turbines, especially for warships, the infrared signal is greatly reduced.

Preferably, the invention also comprises organic-organic heat exchanger, one input end of the heat exchanger is connected to the pressure pump, one output end corresponding to the input end thereof is connected to the intercooler; the other input end of the heat exchanger is connected to one output end of the first throttle valve, the other output end corresponding to the input end thereof is connected to one input end of the first compressor, the heat exchanger conducts heat exchange between the organic working substance input by the pressure pump and the organic working substance input by the first throttle valve. The organic working substance input from the throttle valves is also divided into two paths, one way enters the inlet air cooler and the other enters the organic-organic heat exchanger, and the organic working substance output from the throttle valve also enters this heat exchanger, because the temperature of the organic working substance output from the throttle valve is low, the two organic working substance in the heat exchanger exchange energy, which further reduces the temperature of the organic working substance entering the intercooler and has a better cooling effect to the intercooler.

Preferably, the organic working substance adopts R1336mzz(Z).

The advantageous effects of the invention are as follows:

1. The technical scheme in the invention adopts supercritical organic Rankine cycle as the bottoming cycle of the combined system and forms a combined system with intercooled recuperative gas turbine, which overcomes the problems that when the subcritical organic Rankine cycle and Kalina cycle ammonia water are used as bottoming cycle, there will be respectively constant evaporation temperature of subcritical organic working substance and ammonia water, resulting in insufficient heat exchange and large exergy loss in the intercooler, thereby when the supercritical organic Rankine cycle as the bottoming cycle of the combined system to generate power more efficiently, which can be comparable to the standard three pressure reheat gas-steam combined cycle.

2. In the technical scheme, the supercritical organic Rankine cycle completely got rid of the dependence on the water working substance, saved a lot of water resources, and made it possible to construct a high-efficiency combined power plant in arid areas and for marine propulsion.

3. In this technical scheme, the supercritical organic Rankine cycle is further cascaded and connected with the vapor compression refrigeration cycle, the refrigeration cycle provides a low-temperature organic working substance to adjust the temperature of the inlet air of the intercooled recuperative gas turbine and the temperature of the intercooler coolant, thereby achieving that the gas entering the intercooled recuperative gas turbine is near the design point, the intercooled recuperative gas turbine is operated in the relative stable external environment to make the gas turbine is less affected by ambient temperature changes, thereby ensuring that the entire system maintains a fairly stable output and efficiency under extreme weather conditions.

4. By adopting above structure, the invention has the advantages of faster start-up, quicker load adjustment, and better performance under partial load.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the invention or the technical schemes in the prior art, the drawings of the embodiments or the prior art will be briefly described below. In all accompanying drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to actual scale.

FIG. 1 shows the overall structure of the invention.

In the accompanying drawing: 1 refers to intercooled recuperative gas turbine, 2 refers to organic-gas heater, 3 refers to organic working substance turbine, 4 refers to condenser, 5 refers to pressure pump, 6 refers to first throttle valve, 7 refers to first compressor, 8 refers to organic-organic heat exchanger, 9 refers to inlet air cooler, 10 refers to intercooler, 11 refers to recuperator, 12 refers to organic working substance preheater, 13 refers to second throttle valve, 14 refers to second compressor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiments of the technical schemes of the invention will be described in detail with reference to the drawings. The following embodiments are only used to more clearly explain the technical schemes of the invention, and therefore are only used as examples, and cannot be used to limit the protection scope of the invention.

It should be noted that, unless there are specific statement, the technical or scientific terms used in the invention should be in the ordinary meaning understood by those skilled in the art.

Embodiment

As shown in FIG. 1, the embodiment comprises intercooled recuperative gas turbine 1, organic-gas heater 2, organic working substance turbine 3, condenser 4, pressure pump 5 and organic working substance preheater 12, the organic-gas heater 2 is connected to recuperator 11 of the intercooled recuperative gas turbine 1, the organic-gas heater 2 is connected to the organic working substance turbine 3, the organic working substance turbine 3 is connected to the condenser 4, the condenser 4 is connected to the pressure pump 5, the pressure pump 5 is connected to intercooler 10 of the intercooled recuperative gas turbine 1, the intercooler 10 is connected to the organic-gas heater 2; the intercooler 10 is connected in parallel to the organic working substance preheater 12; the condenser 4 is used for cooling and condensing the organic working substance into liquid and delivering the same to the pressure pump 5, the pressure pump 5 is used for pressurizing the organic working substance to exceed the critical pressure and delivering the same to the intercooler 10, the intercooler 10 is used for preheating the organic working substance and delivering the same to the organic-gas heater 2, the organic-gas heater 2 is used for heating the organic working substance to above the critical temperature and delivering the same to the organic working substance turbine 3, the organic working substance turbine 3 is used for making use of the expansion of the organic working substance and delivering the same to the condenser 4; the organic-gas heater 2 cools the gas input from the recuperator 11 and discharges the same thereafter. The organic working substance preheater 12 and the intercooler 10 are connected in parallel and are used for preheating the organic working substance, mixing the organic working substance together into the organic-gas heater, and raising the temperature of the organic working substance to above the critical temperature.

The embodiment also comprises first throttle valve 6, second throttle valve 13, first compressor 7 and second compressor 14, the throttle valves are connected to the condenser 4, the throttle valves are connected to inlet air cooler 9 of the intercooled recuperative gas turbine 1 through the second throttle valve 13, the inlet air cooler 9 is connected to the first compressor 7 through the second compressor 14, the first compressor 7 is connected to the condenser 4; organic working substance discharged by the condenser 4 enters into the first throttle valve 6 and the second throttle valve 13, and the first throttle valve 6 and the second throttle valve 13 cools the entered organic working substance and discharges the same into the inlet air cooler 9, the organic working substance in the inlet air cooler 9 absorbs heat and enters into the first compressor 7 and the second compressor 14, and enters into the condenser 4 after pressurized by the first compressor 7 and the second compressor 14. The arrangement of two sets of throttle valves and compressors, together with the inlet air cooler, form the intake air cooling subsystem of the gas turbine, further optimizing the performance of the overall device.

In order to achieve a better cooling effect for the intercooler 10, the embodiment further comprises a organic-organic heat exchanger 8, one input end of the heat exchanger 8 is connected to the pressure pump 5, one output end corresponding to the input end thereof is connected to the intercooler 10; the other input end of the heat exchanger 8 is connected to one output end of the first throttle valve 6, the other output end corresponding to the input end thereof is connected to one input end of the first compressor 7, the heat exchanger 8 conducts heat exchange between the organic working substance input by the pressure pump 5 and the organic working substance input by the first throttle valve 6.

In the embodiment, the organic working substance adopts R1336mzz(Z), and the organic working substance in the embodiment may also use other organic working substances.

In the embodiment, the flow rate and heat exchange temperature difference of the supercritical organic working substance are determined according to the air parameters of the compressor intermediate stage and the rear flue gas parameters of the intercooled recuperative gas turbine 1, to ensure not only that the waste heat from the intercooler 10 can be fully absorbed, but also the organic working substance can be heated above the critical temperature in the organic-gas heater 2. The working pressure and temperature of the refrigeration cycle are determined according to the extreme climatic conditions of the entire system, thereby determining the heat exchange duty and area of the heat exchanger 8 and the organic-gas heater 2, in the embodiment, the intercooled recuperative gas turbine 1 adopts air Brayton cycle, and can also adopt an opened or closed air, or other Brayton cycle with other gas substances.

The gas turbine energy may come from fuel chemical energy from combustion or from other heat sources such as concentrating solar energy etc., and the reheater is optional although it is common for intercooling recuperative gas turbine.

The appearance, quantity and size of the invention can be adjusted according to the size of the place of use, but the internal structure and principle remain unchanged.

It should be noted that: the above embodiments are only used to describe the technical schemes of the invention and the invention is not limited thereto; although the invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical schemes described in the foregoing embodiments, or equivalently replace some or all of the technical features; and the modifications or replacements should be within the scope of the embodiments of the invention, and all should be included in the scope of protection of the claims and specification in the invention. 

1. A combined system of intercooled recuperative gas turbine and organic compound bottoming cycle, comprising intercooled recuperative gas turbine (1), organic-gas heater (2), organic working substance turbine (3), condenser (4), pressure pump (5) and organic working substance preheater (12); the organic-gas heater (2) is connected to recuperator (11) of the intercooled recuperative gas turbine (1), the organic-gas heater (2) is connected to the organic working substance turbine (3), the organic working substance turbine (3) is connected to the condenser (4), the condenser (4) is connected to the pressure pump (5), the pressure pump (5) is connected to intercooler (10) of the intercooled recuperative gas turbine (1), the intercooler (10) is connected to the organic-gas heater (2); the intercooler (10) is connected in parallel to the organic working substance preheater (12); the condenser (4) is used for cooling and condensing the organic working substance into liquid and delivering the same to the pressure pump (5), the pressure pump (5) is used for pressurizing the organic working substance to exceed the critical pressure and delivering the same to the intercooler (10), the intercooler (10) is used for preheating the organic working substance and delivering the same to the organic-gas heater (2), the organic-gas heater (2) is used for heating the organic working substance to above the critical temperature and delivering the same to the organic working substance turbine (3), the organic working substance turbine (3) is used for making use of the expansion of the organic working substance and delivering the same to the condenser (4); the organic-gas heater (2) cools the gas input from the recuperator (11) and discharges the same thereafter.
 2. The combined system of intercooled recuperative gas turbine and organic compound bottoming cycle of claim 1, further comprising first throttle valve (6), second throttle valve (13), first compressor (7) and second compressor (14), the throttle valves are connected to the condenser (4), the throttle valves are connected to inlet air cooler (9) of the intercooled recuperative gas turbine (1) through the second throttle valve (13), the inlet air cooler (9) is connected to the first compressor (7) through the second compressor (14), the first compressor (7) is connected to the condenser (4); organic working substance discharged by the condenser (4) enters into the first throttle valve (6) and the second throttle valve (13), and the first throttle valve (6) and the second throttle valve (13) cools the entered organic working substance and discharges the same into the inlet air cooler (9), the organic working substance in the inlet air cooler (9) absorbs heat and enters into the first compressor (7) and the second compressor (14), then enters into the condenser (4) after pressurized by the first compressor (7) and the second compressor (14).
 3. The combined system of intercooled recuperative gas turbine and organic compound bottoming cycle of claim 2, also comprising heat exchanger (8), one input end of the heat exchanger (8) is connected to the pressure pump (5), one output end corresponding to the input end thereof is connected to the intercooler (10); the other input end of the heat exchanger (8) is connected to one output end of the first throttle valve (6), the other output end corresponding to the input end thereof is connected to one input end of the first compressor (7), the heat exchanger (8) conducts heat exchange between the organic working substance input by the pressure pump (5) and the organic working substance input by the first throttle valve (6).
 4. The combined system of intercooled recuperative gas turbine and organic compound bottoming cycle of claim 1, wherein the organic working substance adopts R1336mzz(Z). 